Electric winch device

Abstract

Provided is an electric winch device including: an electric motor; a winch drum; a brake; an operation lever; and a controller. The controller includes: a first torque derivation unit which derives a value of a first torque applied to the winch drum due to a load of an object; a second torque derivation unit which derives a value of a second torque generated in the winch drum by a drive torque of the electric motor; and a brake control unit which determines a timing for releasing a braking action on the winch drum after the operation lever has been operated, on the basis of a differential between the second torque value and the first torque value, and which causes the brake to release the braking action on the winch drum by transmitting, to the brake, a control signal instructing release of the braking action on the winch drum at the determined timing.

Description

TECHNICAL FIELD[0001]The present invention relates to an electric winch device which is used in a crane.BACKGROUND ART[0002]A crane is conventionally provided with a winch device for performing hoisting operations (crane operations). A winch device is provided with a winch drum that rotates by being driven by a motor, and performs hoisting or lowering of an object by means of this winch drum. The hoisting or lowering of the object is instructed by an operator operating an operation lever. In the winch device, the motor performs hoisting or lowering of the object by causing the winch drum to rotate in a hoisting direction or lowering direction, in accordance with the operation of the operation lever.[0003]Furthermore, the winch device is provided with a negative brake. The negative brake holds the winch drum so that the winch drum cannot rotate by applying a braking action to the winch drum, when the operation lever is disposed in a neutral position, and releases the braking action a...

AI Technical Summary

Benefits of technology

The present invention is an electric winch device that prevents the object from slipping or the brakes from being pulled up when the object is being raised or lowered. The technical effect is to improve the safety and stability of the winch system.

Problems solved by technology

However, in a winch device of this kind, there is a possibility that the timing at which the negative brake releases the braking action applied to the winch drum may diverge from the timing at which the motor starts rotation of the winch drum.

In an electric winch device, a winch drum is caused to rotate by using an electric motor instead of a hydraulic motor, and an object is hoisted by the winch drum, but an electric winch device of this kind also has the problems of slipping-down and pull-up phenomena described above.

However, in order to prevent the occurrence of these phenomena in an electric winch device, it is difficult to apply the technologies disclosed in the Patent Documents indicated above.

More specifically, the technologies in the Patent Documents indicated above use hydraulic pressure which is supplied to a hydraulic motor in order to control a brake releasing operation, and cannot be applied to an electric winch device which does not have hydraulic pressure of this kind.

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